THURSDAY, Nov. 29 (HealthDay News) -- Childhood abuse and previous exposure to violence may increase a soldier's risk of developing
post-traumatic stress disorder (PTSD), according to a new study.

Researchers followed 746 Danish soldiers before, during and after they were deployed to Afghanistan. Eighty-four percent of the soldiers showed no PTSD symptoms or recovered quickly from mild symptoms.

The soldiers who developed PTSD were much more likely to have suffered emotional problems and traumatic events at some point in their lives before they went to Afghanistan.

Childhood experiences of violence, especially physical punishment -- abuse -- severe enough to cause bruises, cuts, burns and broken bones, predicted the onset of PTSD in some of the soldiers, according to the study published recently in the journal Psychological Science.

The researchers also found that soldiers who developed PTSD were more likely to have witnessed family violence, and to have experienced physical attacks, stalking or death threats by a spouse. They were also more likely to have past experiences that they would not discuss and were less educated than soldiers who did not develop PTSD.

The findings provide evidence that traumatic experiences prior to deployment in a war zone may predict which soldiers will develop PTSD, and challenge the widely held belief that exposure to combat and war atrocities is the main cause of PTSD, the researchers said.

For some soldiers, army life may provide more social support and life satisfaction than they've had in the past, the researchers noted.

"These results should make psychologists question prevailing assumptions about PTSD and its development," study author Dorthe Berntsen, a psychological scientist at Aarhus University in Denmark, said in a journal news release.

While the study found an association between PTSD in soldiers and past abuse, it didn't prove a cause-and-effect relationship.